Application engineer is someone who works on mostly 4GL stuff like Salesforce but at Google I've seen them do some web development under heavy supervision
Do the AEs need to get hired through coding interviews (of LC difficulty levels)?
Thanks for the comments . Can an App Eng apply for a SWE position via internal interview?
I think anyone can try but that might be a tough jump unless your AE role allows you to demonstrate a good level of proficiency. If you can go SWE now do that
SWE. Always SWE